1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method thereof, and in particular relates to a semiconductor device having co-loaded a DRAM portion and a logic portion and a method of manufacturing the same.
2. Description of Related Art
There is known a semiconductor device having a memory, e.g., a DRAM (Dynamic Random Access Memory) and a logic circuit co-loaded on a semiconductor substrate. For example, Japanese Patent Publication No. JP2000-332216A (corresponding to U.S. Pat. No. 6,965,139 (B2)) discloses a semiconductor device in which a semiconductor memory including a memory cell portion and a peripheral circuit portion and a logic circuit are co-loaded on the same semiconductor substrate. FIG. 1 is a sectional view showing a configuration of this semiconductor device. In this semiconductor device 101, a capacitive element C (124, 125, 126) is formed above bit lines BL (119: 119A, 119B) in the memory cell portion 102. Word lines WL (117) are formed in a direction perpendicular to the bit lines BL. In the peripheral circuit portion 103 and the logic circuit 104, there is formed a first metal layer 128 including an embedded metal layer which is embedded within a connection hole penetrating insulating films 115, 116, 118, 120, 121, 122, 127A (127) and is connected with a diffusion later 113A formed in the semiconductor substrate 110, or connected with a lower layer wiring 114 (114A, 114B) on the semiconductor substrate 110. A first metal wiring layer 129 (129A, 129B, 129C) is connected with the first metal layer 128 and is formed generally in parallel to a main surface of the semiconductor substrate 110. A second metal layer 131 (, 131P, 131Q) including an embedded metal layer 131A (, 131B) embedded within a connection hole penetrating insulating films 127B (127), 130 is formed to be connected with the first metal wiring layer 129. A second metal wiring layer 132(, 132P, 132Q (132A, 132B, 132C)) is formed on the upper insulating film 130 above the capacitive element C and is connected with the second metal layer 131. In the memory cell portion 102, there is formed a groove penetrating insulating layers 127B, 127A sandwiching the first metal wiring layer 129 from above and below the same. The capacitive element C is formed within the groove and on the insulating layers. An N-well 111N, a P-well 111P and STIs 12 are formed in the semiconductor substrate 110.
Moreover, relating to a semiconductor device having co-loaded a memory and a logic circuit, there is disclosed a technique as follows. Japanese Patent Publication No. JP2004-342787A discloses a semiconductor device and a method of manufacturing the same. This semiconductor device is provided with a first interlayer insulating film, a lower electrode contact plug, a second interlayer insulating film, and a capacitor portion. The first interlayer insulating film is formed on a semiconductor substrate. The lower electrode contact plug is formed to penetrate the first interlayer insulating film. The second interlayer insulating film is formed on the first interlayer insulating film. The capacitor portion includes a lower electrode, a dielectric layer and an upper electrode which are formed in a capacitor opening portion penetrating the second interlayer insulating film and reaching onto the lower electrode contact plug. The second interlayer insulating film is formed of a plurality of layers of insulating films. This semiconductor device is further provided with a damascene shaped wiring film containing a copper and an upper layer wiring film formed on the second interlayer insulating film through an upper layer contact hole reaching onto the damascene shaped wiring film. The damascene shaped wiring film is formed on any of the insulating films lower than the upper surface of the second interlayer insulating film. The damascene shaped wiring film has a contact plug embedded in a contact hole. The contact hole penetrates the any of the insulating films, the insulating film below the any of the insulating films and the first interlayer insulating film.
Japanese Patent Publication No. JP2007-201101A (corresponding to U.S. Patent Publication No. 2007173012 (A1)) discloses an integrated circuit device and a method for manufacturing a circuit. In this integrated circuit device, a memory portion including a plurality of capacitive elements and a logic portion including logic circuits are arranged alongside with each other. Each of the capacitive elements includes an upper electrode, a capacitive insulating film and a lower electrode. The memory portion is formed to have a COB (Capacitor over Bit line) structure in which an upper capacitive wiring connected to the upper electrode is positioned above the capacitive elements and a lower capacitive wiring connected to the lower electrode is positioned below the capacitive elements. In this integrated circuit device, the plurality of capacitive elements and at least one logic contact connected to the logic circuit are embedded in an interlayer insulating film. This interlayer insulating film, the logic contact and upper surfaces of the upper electrodes of the plurality of capacitive elements are arranged to form a plane. A logic wiring formed on the plane is connected with the logic contact and the upper capacitive wirings are connected to the upper electrodes of the plurality of capacitive elements.
Japanese Patent Publication No. JP2005-101647A discloses a semiconductor integrated circuit device and a method for manufacturing the same. In this semiconductor integrated circuit device, a MISFET for selecting a memory cell is formed in a memory cell array region on a main surface of a semiconductor substrate, and a MISFET for a peripheral circuit or a MISFET for a logic circuit is formed in a peripheral circuit region or a logic circuit region of the semiconductor substrate, respectively. A first insulating film is so formed as to cover the MISFET for selecting a memory cell and the MISFET for the peripheral circuit or the MISFET for the logic circuit. Bit lines are formed on the first insulating film in the memory cell array region and a first layer wiring made of the same material as the bit lines is formed on the first insulating film in the peripheral circuit region or the logic circuit region. A second insulating film covering the bit lines and the first layer wiring and having its surface flattened is formed on the memory cell array region and the peripheral circuit region or the logic circuit region. An etching stopper film covering the second insulating film is formed on the memory cell array region and the peripheral circuit region or the logic circuit region. A third insulating film is formed on the etching stopper film. The third insulating film of the memory cell array region is provided with a lower electrode, a capacitive insulating film covering the lower electrode and an upper electrode of a capacitive element for accumulating information. A fourth insulating film is formed on the third insulating film, the capacitive element for accumulating information and the peripheral circuit region or the logic circuit region. The etching stopper film does not exist under the lower electrode but exist in the region on the second insulating film in a state of contacting a side wall of the lower electrode so that the etching stopper film functions as an etching stopper when etching the third insulating film.
Japanese Patent Publication No. JP2005-86150A discloses a semiconductor device and a manufacturing method thereof. This semiconductor device includes a semiconductor substrate, a first insulating film formed on the semiconductor substrate, a capacitor formed on the first insulating film, and a second insulating film cover ring the capacitor, which is of a composition different from that of the first insulating film. A contact hole is formed in the first insulating film by etching the first insulating film with the second insulating film serving as a mask.
Japanese Patent Publication No. JP2005-5337A discloses a manufacturing method of a semiconductor integrated circuit device with a co-loaded DRAM. In this manufacturing method of a semiconductor integrated circuit device with a co-loaded DRAM, a DRAM portion and a peripheral logic portion are formed on a semiconductor substrate. The manufacturing method of a semiconductor integrated circuit device with a co-loaded DRAM includes: a first step of forming a gate electrode on the semiconductor substrate through a gate insulating film and forming a source/drain implantation layer in the semiconductor substrate; a second step of depositing a first nitride film on the semiconductor substrate including the gate electrode, depositing a first interlayer insulating film on the first nitride film, forming a first contact hole which penetrates the first nitride film and the first interlayer insulating film to reach the source/drain implantation layer, and forming a first plug within the first contact hole; a third step of depositing a second nitride film on the semiconductor substrate provided with the first plug and a second interlayer insulating film on the second nitride film, etching a capacitor formation portion of the deposited second nitride film and the second interlayer insulating film so as to reach the first plug, depositing a first conductive film on the etched capacitor formation portion, and forming a capacitor lower electrode by etching back overall the deposited first conductive film and remaining the first conductive film on a side wall and a bottom portion of the capacitor formation portion; a fourth step of depositing a dielectric layer on the capacitor lower electrode and a second conductive film on the dielectric layer, and forming a capacitor upper electrode only on the side wall and the bottom portion of the capacitor formation portion by etching back or CMP (Chemical-Mechanical Polishing) of the deposited second conductive film; a fifth step of forming a second contact hole at a bit line contact portion so as to penetrate the second nitride film and the second interlayer insulating film to reach the first plug, and forming a second plug within the second contact hole; and after the fifth step, a sixth step of forming a wiring above the second interlayer insulating film through an insulating film for connecting all of the capacitor upper electrodes of the DRAM portion.
Japanese Patent Publication No. JP2004-63559A (corresponding to U.S. Pat. No. 6,770,930 (B2)) discloses a semiconductor device. This semiconductor device has a multilayer structure. This semiconductor device includes: a capacitor disposed in an upper main surface of a first region of an interlayer insulating film; and a wiring layer disposed in an upper main surface of a second region of the interlayer insulating film. The capacitor includes: a capacitor upper electrode provided to be embedded in the upper main surface of the first region of the interlayer insulating film; a capacitor dielectric layer provided to cover at least a side surface and a lower surface of the capacitor upper electrode; and at least one lower electrode-and-plug electrically connecting the capacitor to a configuration provided under the capacitor and having a portion inserted in a thickness direction of the capacitor upper electrode, the inserted portion functioning as a capacitor lower electrode. The capacitor dielectric layer further covers a surface of the inserted portion of the at least one lower electrode-and-plug. The wiring layer is electrically connected to a configuration provided under the wiring layer by at least one contact plug having a portion inserted in a thickness direction of the wiring layer.
I have now discovered the following facts.
In recent years, as developments of semiconductor devices have been progressed to be finer and finer, there have been increasing severe demands for steps, sizes and margins in designing. In a semiconductor device having a DRAM portion and a logic portion co-loaded with each other, there arises an undesirable matter that a height of a wiring layer in the logic portion and a height of an upper surface of a capacitor in the DRAM portion are different in level in a manufacturing process. In the case of the semiconductor device shown in FIG. 1, there arises a step, for example, between a surface of D2 and a surface of D1 in height level. Under this condition, if a height of a via 131P connected to a capacitance plate E in the DRAM portion 102 and a height of a via 131Q in the logic circuit 104 are both intended to be made to correspond to a reference of a wiring design parameter (e.g., a reference for defining a via height and a wiring height to be constant in each layer), it may be considered to make the thickness of the interlayer film 130 uniform between the DRAM portion and the logic portion. However, in this case, there occurs a step in the interlayer film 130 at a contacting portion between the surface of D2 and the surface of D1. If so, it is difficult to connect wirings on the interlayer film 130 thereafter, and a process of forming a wiring by CMP thereafter also becomes difficult.
In order to avoid such a step on the interlayer film 130 as described above, it may be considered to make only the height of the via 131P in the DRAM portion correspond to a reference of a wiring design parameter. In this case, however, the height of the via 131Q in the logic portion becomes higher than the reference by a difference corresponding to the step. Meanwhile, it may be considered to make only the height of the via 131Q in the logic portion correspond to the reference mentioned above. In this case, however, the height of the via 131P in the DRAM portion becomes lower than the reference by a difference corresponding to the step (as shown in FIG. 1 for example). If so, a resistance of the via is out of the corresponding reference. In this manner, since there exists a variation in height corresponding to a step at a portion (e.g., the via in the DRAM portion) which cannot be treated using the wiring design parameter, it is difficult to predict a resistance value. Particularly, in the case where the portion (e.g., the via in the DRAM portion) containing a variation in height and the portion (e.g., the via in the logic portion) containing no variation in height are simultaneously deigned, there may easily cause an error. That is, since the configurations of the vias in the wiring layers (including a via layer with a via and a metal layer with a metal wiring) provided on and above the surface of the capacitance plate are not the same between the DRAM portion (capacitance plate) and the logic portion, it becomes difficult to predict the resistance value of the via and an error may be easily caused.